The visual principle of a 3D stereoscopic image is based on the fact that the left eye and the right eye of a human being respectively receive images of different views, and then a stereoscopic image with a depth and a distance sense is presented in the human brain by using binocular parallax through the brain. The 3D stereoscopic image displaying technique is developed based on such a principle.
The conventional methods for generating a 3D stereoscopic image may be approximately divided into two types. In the first method, a plurality of cameras disposed at different positions is used to simulate the circumstance that the eyes of a human being capture images of the same object from different view angles. Each camera captures a view image corresponding to a specific view angle. The two view images are synthesized a 3D stereoscopic image. Then a device, for example, polarized glasses, is used to guide the two view images to the left eye and the right eye of the human being respectively. The 3D stereoscopic image with a depth and a distance sense is generated in the human brain. In the other method, a 2D image and a depth map are used to synthesize a 3D stereoscopic image. The depth map records depth information of each pixel in the 2D image. The synthesized 3D stereoscopic image is displayed by a 3D stereo display. Accordingly, a 3D stereoscopic image with a depth and a distance sense is presented in the human brain when the image is observed by an observer with naked eyes. In the other aspect, a multi-views 3D stereoscopic image can be displayed according to arrangement positions of the pixels of a 3D stereoscopic image in a 3D stereo display by using a special hardware design of the 3D stereo display.
In the process of synthesizing a multi-views 3D stereoscopic image by using a 2D image and a depth map, the problems about image processing speed and usage of memory capacity must be considered. Taking a 3D stereoscopic image with 9 views as an example, the processing sequence in an existing method is as shown in FIG. 1. In a first step, a source 2D image 10 and depth information in a depth map 11 are used to generate nine view images 21-29 through operation, and then the nine view images 21-29 are used to synthesize a 3D stereoscopic image 30 with nine views. During the synthesizing process, a large memory capacity is required to store nine view images 21-29, and in the other aspect, since a large number of view images 21-29 perform accessing in the memory, the data processing speed is slowed down. For example, after the view images 21-29 are obtained by using the source 2D image 10 and the depth map 11 through operation, firstly, the generated view images 21-29 are written into the memory, and then during the synthesizing process of the multi-views 3D stereoscopic image 30, the view images 21-29 previously stored in the memory need to be used, so that the view images 21-29 are further read from the memory. As a result, the frequent memory reading and writing actions cause the processing speed to be slowed down.
Taking the prior art shown in FIG. 1 as an example, it is assumed that a 2D image at an input end has a resolution of 640×360 pixels, a 3D stereoscopic image 30 at an output end has a resolution of 1920×1080 pixels, and during the synthesizing process, nine different view images are generated, each of which has a resolution of 640×360 pixels. Accordingly, it can be derived that each view image requires a memory capacity of 640×360×24 bits=5,529,600 bits, and thus the total memory capacity required by the nine view images 21-29 is 9×5,529,600 bits, which is about 50 M bits, and if the memory capacity required by the images at the input end and the output end, that is, 2×(55,296,000+49,766,400), is further added, it is totally about 210 M bits. Thus, a large memory capacity is required for storing image information.